Device for Gripping and Transporting Pipe Lengths and an Intermediate Storage Facility for Storage of Pipes

ABSTRACT

A pipe gripping device for gripping and transport of pipe lengths. The device comprises at least one gripper having two opposite gripping jaws. The gripping jaws have at least two expansions, each of which is adapted to grip a pipe length, thus allowing the gripper to grip at least two pipe lengths at the same time. In addition, a description is given of an intermediate storage facility for intermediate storage of pipe lengths, which is arranged as a mezzanine storage between the drilling position on a drilling deck and a main pipe rack.

The present invention regards devices for handling of pipes, especially for handling pipes between a pipe rack and a derrick in connection with the production of petroleum products, in accordance with the preamble of Claim 1.

Hereinafter, the term pipe length will refer both to single pipes and stands.

When producing petroleum products, use is made of a drilling derrick, which forms part of a rig. The rig may be situated either onshore or offshore. Offshore, the rig may be a fixed structure standing on the seabed, or it may be a floating structure which is either tethered to the seabed or dynamically positioned.

The main function of the drilling derrick is to provide suspension for winching equipment that is used to lower a drill string, riser, casing and other continuous pipe strings down to or into a well, as well as lifting the drill string out of the well.

A time-critical factor of drilling operations and other operations that involve lowering and retrieval of a long pipe string (“tripping” in technical terminology) is the transport to and from the drilling derrick. It has therefore been desirable to store stands (consisting of 2, 3 or 4 drill pipes) as close to the derrick as possible. However, space is highly restricted in this area, as other essential equipment must also be stored here. Another argument for moving the stands away from the actual drilling deck is that placing them at a lower level would lower the centre of gravity. Thus these storage racks near the drilling derrick can hold only a limited number of pipes.

Much effort has gone into developing equipment that will provide rapid transport of stands to the drilling derrick, in some cases directly to the drilling centre (the line followed by the pipe string through the derrick). It is equally important to be able to quickly remove pipes that have been detached from the pipe string.

In the development of this type of pipe handling equipment great emphasis has also been placed on the safety aspects involved. Consequently more and more automated equipment has been developed, requiring a minimum number of personnel on the drilling deck.

Despite the above efforts that have been put into development work, the pipe handling to and from the derrick is still a bottle neck.

The present invention aims to provide a system that will further reduce the time wasted when handling pipes and stands to and from the derrick. This is achieved by the characteristics stated in the characterizing part of the following Claim 1.

Norwegian patent application no. 2004 5263 from the same applicant describes a device associated with the drilling deck, which is arranged to receive a pipe for intermediate storage. This device is well suited for use with the devices of the present invention.

The invention will be explained in greater detail with reference to the accompanying drawings, in which:

FIG. 1 is a front elevation of a section of a drilling derrick and a drilling deck, showing transportation means for pipe lengths;

FIG. 2 is a plan view of an arm of a gripping device for simultaneous handling of two pipes;

FIG. 3 is a front elevation of an intermediate storage facility for pipe lengths; and

FIG. 4 is a plan view of the intermediate storage facility of FIG. 3.

FIG. 1 illustrates part of a drilling derrick 1. The drilling derrick rests on a drilling deck 2. Suspended in the drilling derrick 1 is a block (not shown), which forms part of a draw works. The block is arranged to move vertically along a drilling axis extending through the derrick 1. From the block there is suspended a top drive (not shown). A drill string may be suspended from the top drive, which drill string extends along the drilling axis, through a rotary 3 and down to the seabed.

FIG. 1 also shows a control room 4, from which the drilling operation and pipe handling are controlled.

Outside of the drilling deck 2 and at a lower level than this, preferably on a platform deck 5, there is provided a pipe rack 6. The pipe rack 6 can hold a number of pipe lengths 7. The pipe lengths may be two or more drill pipes screwed together to form stands, one or more liners, drill collars or other tubular members.

By the pipe rack there is arranged a first pipe gripping device 8. This may be constructed generally as a so-called column machine, which comprises a rotatable column 9 equipped with at least two grapplers/gripping arms 10, 11. The gripping arms 10, 11 are vertically spaced apart on the column 9 and are arranged for joint gripping of pipe lengths 7. The arms 10, 11 can be moved out from the column 9, e.g. through being articulated. Preferably they can also move a little in the vertical direction along the column 9, to allow them to adjust and grip different lengths of pipes.

FIG. 1 also shows an intermediate storage facility 12 arranged to receive pipe lengths 7. The intermediate storage facility 12 is positioned just outside the edge of the drilling deck 2 and at a level between the drilling deck 2 and the platform deck 5.

On the drilling deck 2 there is provided a second pipe gripping device 13. This may be of the same type as the first pipe gripping device 8. Thus the detailed description of one of these pipe gripping devices also applies to the other pipe gripping device.

Below the drilling deck 2 there is provided a rotatable mousehole device, which will not be explained in any greater detail herein, as it has been explained in detail in the above-mentioned Norwegian patent application no. 2004 5263. This application is hereby incorporated in the present by reference.

FIG. 2 shows a plan view of an arm 10 for a pipe gripping device 8, 13. The arm 10 comprises an articulated mechanism 14 that is known per se and a column trolley 15. The construction and operation of these will be well known to a person skilled in the art, thus they will not be explained in greater detail herein.

At the outer end of the arm 10 there is arranged a gripper 16. The gripper comprises two halves in the form of gripping jaws 16 a and 16 b, which can be swivelled relative to each other in a manner that is known per se, in order to provide distance between the halves 16 a, 16 b.

Each jaw 16 a, 16 b comprises two cavities 17 a; 17 b, 18 a; 18 b generally shaped as a C, e.g. as sectors of a circle, with an intermediate portion 19. When the halves 16 a, 16 b have been brought together as shown in FIG. 2, the cavities 17 a; 17 b, 18 a; 18 b form generally circular expansions 17, 18 of a diameter slightly smaller than that of a pipe 7. The inside of the cavities 17, 18 may be coated with a high friction lining 20.

Optionally there may be more cavities formed on the gripper 16, to allow it to grip more than two pipes 8 at the same time.

The first pipe gripping device 8 is arranged to transport pipe lengths 7 between the pipe rack 6 and the intermediate storage facility 12, while the second pipe gripping device 13 is arranged to transport pipe lengths 7 between the intermediate storage facility 12 and the drilling derrick, preferably all the way to the drilling axis.

As mentioned above, the intermediate storage facility 12 is placed at a level between the drilling deck 2 and the platform deck 5. Thus the intermediate storage facility 12 forms a mezzanine storage that act as an intermediate station for pipe lengths 7. Having such an intermediate station makes it unnecessary for the first and second pipe gripper devices 8, 13 to act synchronously, allowing them to transport pipes at their own pace and independently of each other. The only condition for this is that the intermediate storage facility 12 must not become completely empty or full.

The intermediate storage facility 12 is shown in greater detail in FIGS. 3 and 4. It comprises a finger board 21 with room for pipe lengths 7, such as drill pipes, liners, drill collars and similar. The finger board projects from a support 25 positioned near the edge of the drilling deck 2, causing the finger board 21 to project mainly outside the drilling deck 2. The finger board 21 may be adjusted in order to receive pipes of different diameters. FIG. 4 shows the finger board 21 from above. In the example, the finger board comprises three fingers 22, 23, 24. Between each finger 22, 23, 24 there is a space that is slightly larger than the diameter of the pipes 7 to be held here.

Holders 26 have been provided along two of the fingers 22, 24. The holders are spaced at intervals which are such that they allow a pipe 7 to be placed between each holder 26. The holders may be swung up over the finger 22, 24 in order to allow the pipe 7 to pass, thus making it possible to transport pipes past the holders 26.

A distance below the finger board 21 there is provided a deck 27, which is arranged to support pipe lengths 7. Preferably the deck has a small raised edge to allow the deck 27 to collect waste water. On two sides of the deck 27 there are railings 28. The railings act as safety devices, preventing the lower end of the pipe lengths 7 from moving sideways off the deck 27. There may be recesses or pins formed on the deck 27, each of which is arranged to receive the lower end of a pipe length 7.

Optionally a system can be installed to pull the pipe lengths 7 back and forth along the fingers 22, 23, 24 and the deck 27. This can be achieved by means of e.g. a rubber belt placed on the deck 27, rollers in the deck and conveying belts on the sides of the fingers, or by means of rollers and cylinders.

By using the intermediate storage facility 12 as an intermediate storage area for pipe lengths 7 it becomes possible safely and quickly to transport pipe lengths 7 from one position to another, over a great distance and height difference. This system makes it possible to fill the intermediate storage facility, allowing the making or breaking of a drill string to be carried out as a continuous process.

Alternatively the first and the second pipe gripping device 8, 13 can reach all positions in the intermediate storage facility 12.

Pipe lengths 8 are transported from the pipe rack 7 by means of the first pipe gripping device 8. The pipe gripping device 8 places the pipes in the intermediate storage facility 12. The second pipe gripping device 13 retrieves pipes from the intermediate storage facility 12 and transports them to the drilling centre. Thus the intermediate storage facility 12 serves as a buffer between the two pipe gripping devices 8, 13. If both pipe gripping devices 8, 13 can grip and transport two pipe lengths at the same time, the pipe conveying capacity will double. Although it is advantageous for both pipe gripping devices to be able to transport two pipes at the same time, it is also possible that only one of them will have this capacity. It is also possible to utilise the intermediate storage facility 12 in combination with conveying equipment that can only transport one pipe length. 

1. A device for gripping and transporting pipe lengths between a storage and a drill floor, comprising at least one gripper having two opposite gripping jaws, characterized in that the gripper has at least two expansions that are arranged one after the other along the dividing line between the two gripping jaws, the gripping jaws having a portion between two adjacent expansions where the distance between the two gripping jaws, when brought together, is smaller than the largest dimension of the expansions, each of the expansions being adapted to grip a pipe length, allowing the gripper to grip at least two pipe lengths simultaneously.
 2. A device according to claim 1, characterized in that each expansion is formed by two opposing cavities, one formed in each griping jaw.
 3. A device for intermediate storage of pipe lengths, characterized in that the storage facility is arranged as a mezzanine storage at a level between a place of use and a place of permanent storage.
 4. A device according to claim 3, characterized in that the place of use is a drilling deck and the place of permanent storage is a main pipe rack on a platform deck, and that the intermediate storage facility is arranged at a position between the main pipe rack and the centre of the drilling deck.
 5. A device according to claim 4, characterized in that the intermediate storage facility is arranged at the edge of the drilling deck, protruding partly above the drilling deck and partly below the drilling deck.
 6. A device according to claim 3, characterized in that it comprises a deck arranged for support of the lower ends of pipe lengths, and a finger board arranged at a vertical distance from the deck.
 7. A device according to claim 6, characterized in that the finger board comprises fingers equipped with holders that leave room for one pipe between adjacent holders.
 8. A device according to claim 7, characterized in that the holders can be swung over the fingers to allow a pipe to pass.
 9. A device according to claim 6, characterized in that the deck is provided with safety devices on at least two sides, which prevent the lower ends of the pipe lengths from moving outside the deck.
 10. A device according to claim 4, characterized in that it comprises a deck arranged for support of the lower ends of pipe lengths, and a finger board arranged at a vertical distance from the deck.
 11. A device according to claim 5, characterized in that it comprises a deck arranged for support of the lower end pipe lengths, and a finger board arranged at a vertical distance from the deck. 